The OLED (Organic Light-Emitting Diode) is the new generation solid self-emissive display technology. In comparison with liquid crystal display, it possesses advantages of ultra-thin, fast response, high contrast, low power consumption and etc. The industry has rapidly developed in the recent years. At present, the mainstream manufacture skill and method of the OLED is evaporation, which is to heat organic small molecule material in a vacuum chamber to be sublimated or gasified to be material vapor. Then, it is deposed on the glass substrate with the opens of the metal mask. With the evaporators of newer and newer generation appear, the utilized crucible becomes larger and larger. The heating coil of the heating source becomes larger and larger, too. The distribution of the coil also gets more and more integrated. Because the expanding with heat and contracting with cold of the heating coil itself, the crucible loaded with material experiencing expanding with heat and contracting with cold can cause the partial deformation of the crucible. The adjacent heater strips of the heating coil deform due to these external forces, which can results in the mutual contact and cementation. The short circuit of the entire heating source happens to cause the abnormal downtime of the evaporator and to seriously affect the stability of the evaporator.